The present invention relates generally to semiconductors, and more specifically, to treating copper interconnects of semiconductors.
Semiconductor-based integrated circuits consist of several layers, such as back-end-of-line (BEOL) levels which provide power to the underlying devices that reside in the front-end-of-line. Copper or other conductive materials comprise the interconnect metallization in the BEOL levels. Because copper is a better conductor than aluminum, chips using copper interconnects can have smaller metal components, dissipate less energy to pass electric current through them and can exhibit higher speed signal transmission. Accordingly, copper interconnects are ideal for use in higher-performance processors.
Electromigration has become a concern as integrated circuit component sizes become smaller. Electromigration is a process by which atoms within a conductive material diffuse under the influence of an electric current flowing through it. Eventually, electromigration can cause voids to form in the material and can lead to open circuit failure within the conductor. Resistance to electromigration can be better in copper than in aluminum. Superior electromigration resistance allows higher currents to flow through a given volume of a copper conductor compared to the same volume of an aluminum conductor. Accordingly, copper-based interconnects are used throughout the semiconductor industry.